Hi @thelucash ，
and that notifications were enabled in both outlook and the windows notification menus
By this, do you mean you have already confirmed that the Outlook Notifications are enabled through Windows (Start > Settings > Notifications & Actions) and the Display a Desktop Alert option is selected in Outlook? See Turn new message alert pop-up on or off.
If all these have been checked but the issue persists, it's worth trying to create a new Outlook profile and then adding the user's account to see if there would be any improvement.
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